Which of the following is known as a baker in Latin?

The term known as a baker in Latin is "pistor." This word specifically refers to someone who bakes bread or other baked goods, highlighting the important role bakers played in Roman society. The profession was significant not only for daily sustenance but also for various festivities and occasions where baked goods were essential.

The other terms have distinct meanings unrelated to baking; "publicanus" refers to a tax collector, a role often associated with collecting taxes on behalf of the Roman state. "Caupo" denotes an innkeeper or tavern owner, someone responsible for hospitality and serving food and drink. "Tonsor" translates to a barber, indicating a profession focused on grooming rather than food production. Thus, "pistor" is the only term that directly relates to the profession of baking.